Unwelcome Guest: Airborne Staph in Homes

Unwelcome Guest: Airborne Staph in Homes

Article excerpt

Staphylococcus aureus, one of the most prevalent causes of infections of the blood, skin, soft tissue, and lower respiratory tract, spreads through close contact with contaminated people and surfaces. Although a few studies hint that airborne transmission of the microbe may be involved in hospital infections, no studies have examined indoor levels of S. aureus outside of a hospital setting. The first study to monitor S. aureus bioaerosols in residences shows that strains of the bacterium are common inhabitants of indoor and outdoor air [EHP 114:1859-1864; Gandara et al.]. Moreover, indoor strains are particularly resistant to commonly prescribed antibiotics.

During March, April, and May 2006, researchers cultured S. aureus from bioaerosol samples collected at 24 one-story homes in El Paso, Texas. They treated the bacterial colonies with three common antibiotics--ampicillin, penicillin, and cefaclor--to assess drug resistance.

All the indoor samples contained airborne S. aureus, as did nearly half of the outdoor samples. S. aureus levels inside the homes averaged 15.39 colony-forming units (CFU) per [m.sup.3] air, and outdoor samples averaged 12.63 CFU per [m.sup.3]. About half the indoor samples were resistant to ampicillin, 60% were resistant to penicillin, and 13% were resistant to cefaclor. …